Diatomaceous earth consists of the skeletal or fossilized remains of diatoms, which are microscopic, flowerless water plants related to algae. Diatoms were an early form of life on earth and remain abundant today. They are too small to be seen individually without magnification. Collectively, they will often appear as a brown growth on the surface of stagnant water, mud, rocks, seaweed, or wherever light and water have coexisted for a sufficiently long time for diatoms to propagate and accumulate. Diatoms live in both fresh and salt water.
Over a long period of time, decaying diatoms accumulate on lake and sea beds. In many areas of the world, ancient lake or sea beds, which are now on dry land, contain massive layers of fossilized diatoms. These layers are mined as diatomaceous earth.
Diatomaceous earth is nearly pure silica and has a chalky or flour-like feel when rubbed between one's fingers. A microscopic examination of the fossilized diatoms making up diatomaceous earth would reveal that they are small particles having numerous sharp edges and splines.
Since fossilized diatoms originally consisted of vegetable matter, diatomaceous earth is non-toxic to humans and animals if ingested, and is otherwise harmless because of the small size of diatoms. For this reason, diatomaceous earth is sometimes called "fossil flour" because of its use as animal feed, and its reported use as a flour supplement in baking bread in certain impoverished countries.
Diatomaceous earth has enjoyed many other kinds of uses as well. For example, it has been used as an additive for concrete, as an insulating material, and has enjoyed widespread use as a filtering agent. As will become apparent, the present invention relates to the latter use.
Approximately 40 years ago, it was discovered that diatomaceous earth could serve as an effective insecticidal agent. Unlike human beings and other animals, insects have exoskeletons. Basically, an insect exoskeleton is a hard but porous cover which contains and protects vital internal fluids. The exterior surface of the exoskeleton is covered and protected by an oily or waxy layer which seals it and prevents the escape of moisture and internal fluids.
If an object is small and sharp enough, it will scratch the covering layer, thereby allowing the internal fluids to escape from inside the exoskeleton. The resultant effect is that the insect will dehydrate and die. Consequently, the sharp, microscopic edges of the diatom particles making up diatomaceous earth can be fatal to insects upon contact. The obvious advantage that diatomaceous earth offers over chemical insecticidal agents is that diatomaceous earth is entirely mechanical and non-toxic in the way it kills insects.
Breweries use milled diatomaceous earth as a filtering agent in connection with making beer. When used for such purpose, the diatomaceous earth must be replaced periodically because it eventually becomes clogged with filtered organic matter. It is not reusable and has created a disposal problem for the brewing industry.
It is believed that, in most cases, breweries ship their unusable diatomaceous earth to landfills for burial. This is costly from the standpoint of shipping and handling. Because of its non-toxic nature, and since the filtered organics contain sugars, yeasts, and proteins which have nutritional value, in some cases the used diatomaceous earth has been fed to animals. In this respect, and for the same reason that diatomaceous earth is fatal to insects, it is believed that such use helps to control certain internal parasites in animals. However, it is not believed that the demand for use as animal feed is sufficient to utilize more than a small percentage of total brewery waste output.
The present invention addresses the above brewery disposal problems. For the reasons stated above, it is admittedly well-known in the prior art for nurseries and others to use freshly mined and milled diatomaceous earth as a soil additive or amendment for the purpose of insect control. However, diatomaceous earth is not suitable for such use after it has been used as a filtering agent in a brewery.
If the used filtering agent is added to or mixed with soil, the retained organics which were filtered would cause molds and fungal diseases to develop in the soil. The retained organics would also create a physical change in the soil that would inhibit proper soil porosity. With respect to insect control, the retained organics fill the spaces in between the edges of the fossilized diatoms making up the filtering agent, blunting their effectiveness with respect to their ability to scratch the outer covering of an insect exoskeleton. Last, the filtered organics also have a very rancid smell which makes it undesirable to use them as part of a soil additive near residences.
For the reasons stated above, diatomaceous earth having a prior use as a filtering agent in a brewery is not suitable nor effective for use as an insecticidal soil amendment. The purpose of the present invention, therefore, is to convert the used filtering agent into a form that will be suitable for such use. The practical advantage the invention provides to nurseries is that an excellent product is created from the standpoint of producing a soil amendment that adds to soil quality and fertility, while, at the same time, provides a degree of non-toxic insect control. The commercial advantage is that filtered diatomaceous earth can be obtained from breweries at little cost in comparison to obtaining freshly mined diatomaceous earth. How the invention accomplishes the above advantages and objectives is disclosed below.